This is the moral hazard problems that are created in the financial sector when large financial institutions (in terms of asset value) realise that any losses they make will be paid by the taxpayer they increase their propensity for risk. For example in the case of Northern Rock the Bank of England provided them with a £3bn bailout to keep them alive. However if large banks receive the guarantee that they will always be bailed out they have no incentive to stave off losses.